During the U.S. Mint’s 2013 anti-counterfeiting review of American currency, the following alterations were rejected as too expensive or complicated:

Textured “hair” on the President or dignitary featured on the bill. It would have the added benefit of helping blind people who could use “George Washington’s fluffy cloud of hair” and “Abraham Lincoln’s scraggly beard” to differentiate between the one and five dollar bills.

Scratch-and-sniff whiskey scent on the Andrew Jackson $20.

Embedded musical chip that would play “You’re in the Money!” whenever a bill is unfolded.

Fireproof paper which would make the phrase “money to burn” obsolete.

Holographic image that would wink whenever the bill is turned sideways.